How to make JavaScript execute before page load?
Question
I have this code
<html>
<head>
<script>
function main(){
function loadWordlist(url){
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
console.log('firstFunction');
}
};
xhttp.open("GET", url, true);
xhttp.send();
}
loadWordlist('https://www.example.com/');
}
main()
</script>
</head>
<body>
<script>
console.log('secondFunction')
</script>
</body>
<html>
Here i am getting the content from the url And during that the browser contain loading the code and execute it
But i get secondFunction first then firstFunction And i want firstFunction to execute first then secondFunction after firstFunction finish
1 answers
solution1
3 ACCPTED 2023-01-14 13:47:30
Call the second function from the first function.
<html>
<head>
<script>
function main(){
function loadWordlist(url){
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
console.log('firstFunction');
secondFunction();
}
};
xhttp.open("GET", url, true);
xhttp.send();
}
loadWordlist('https://www.example.com/');
}
main()
</script>
</head>
<body>
<script>
function secondFunction() {
console.log('secondFunction');
}
</script>
</body>
<html>
If that's not possible, you can make xhttp.send() blocking. I strongly advise against it. It's bad user experience. But it's possible, and maybe there are use-cases where this is the only solution.
<html>
<head>
<script>
function main(){
function loadWordlist(url){
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
console.log('firstFunction');
}
};
xhttp.open("GET", url, false);
xhttp.send();
}
loadWordlist('https://www.example.com/');
}
main()
</script>
</head>
<body>
<script>
console.log('secondFunction')
</script>
</body>
<html>
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